Exemplary embodiments of the invention relate to a device for displaying moving images in a motor vehicle, a motor vehicle and a method for displaying moving images in a motor vehicle.
The known “COMAND” infotainment system for the passenger vehicles made by Mercedes-Benz comprises a color display, which is arranged in the center console or alongside the instrument cluster above the center console, a market-specific TV tuner (nowadays DVB-T, DTMB, ISDB-T, for example), and a DVD player. In the so-called “TV operation”, television broadcasts can be displayed on the color display by the TV tuner and in the so-called “DVD video operation”, films can be displayed by the DVD player. This known infotainment system has so-called “automatic image cutout”, which causes the display of the moving images on the color display to be switched off when the driving speed exceeds 5 km/h and instead causes explanatory information to be shown on a black background in the color display, and causes the display of the moving images on the color display to be switched on again when the driving speed falls below 3 km/h. The risks resulting from driver distraction should hereby be reduced.
A disadvantage of this known infotainment system is that the display of the information on a black background is very dark and the abrupt change from the normal display or playback of the moving images to this dark display, and vice versa, may distract or bother the driver, such that he may often just attempt, in a traffic jam or slow-moving traffic, to adapt his driving profile to the algorithm of the automatic image cutout. This represents a driver distraction, whereby the risk of accident increases.
Exemplary embodiments of the invention are directed to further reducing the risks caused by driver distraction.
According to a first aspect of the invention a device for displaying moving images in a motor vehicle comprises                at least one screen for displaying the moving images, to which at least one moving image source can be or is connected for the moving images;        a control unit for the screen, which activates or can activate the screen in at least one first mode, in which the moving images are displayed with normal playback parameters, and one second mode;        
wherein                at least one speed sensor can be or is connected to the control unit, which detects or can detect the speed of the motor vehicle and transmits or can transmit it to the control unit;        the control unit selects the first mode if the speed is less than a first threshold value;        the control unit selects the second mode if the speed is greater than or equal to a second threshold value that is greater than or equal to the first threshold value;        in the second mode, the refresh rate is lower than in the first mode.        
The lower refresh rate leads to a lower level of driver distraction than the abrupt change to the dark image in the known “COMAND” infotainment system, and to an attractive depiction or display on the screen.
The moving image source can, according to need, be connected to the screen in any manner, for example directly or indirectly, in particular via the control unit.
The playback parameters that are used for the display and playback of the moving images comprise, for example, the refresh rate, the image resolution, color depth and brightness.
The control unit can, according to need, be formed in any way, for example in such a way that it activates or can activate the screen in at least one further mode and selects each of these further modes depending on at least one further condition, which in particular comprises a further threshold value for speed and this further threshold value being exceeded. Thus, provision can be made, for example, for the control unit to activate or be able to activate the screen in a third mode, wherein information on a dark, in particular black, screen is displayed, and selects the third mode if the speed is greater than or equal to a third threshold value that is greater than or equal to the second threshold value.
An exemplary system can also include                at least one distance sensor to be or be able to be connected to the control unit, which detects or is able to detect the distance of the motor vehicle from an object located in front of the motor vehicle in the direction of travel and/or from a vehicle travelling in front, and transmits or is able to transmit it to the control unit;        the control unit to change or be able to change the first and/or the second threshold value according to an isotone function of the distance.        
An “isotone” function also means a “monotonically increasing” function. Since the control unit changes or can change the first and/or the second threshold value according to an isotone function of the distance, it enlarges the respective threshold value or leaves it unchanged if the distance detected by the distance sensor and transmitted to the control unit increases, and it reduces the respective threshold value or leaves it unchanged if the distance detected by the distance sensor and transmitted to the control unit decreases. This isotone change can take place, according to need, in any manner, for example in stages with at least one stage, or continuously, in particular in proportion with, disproportionately lower or disproportionately higher than the distance.
An exemplary system can further include                at least one relative speed sensor to be or be able to be connected to the control unit, which detects or can detect the relative speed of the motor vehicle with respect to a vehicle travelling in front and transmits or can transmit it to the control unit;        the control unit to change or be able to change the first and/or the second threshold value according to an antitone function of the relative speed.        
An “antitone” function also means a “monotonically decreasing” function. Since the control unit changes or can change the first and/or the second threshold value according to an antitone function of the relative speed, it reduces the respective threshold value or leaves it unchanged if the relative speed detected by the relative speed sensor and transmitted to the control unit increases, and it enlarges the respective threshold value or leaves it unchanged if the relative speed detected by the relative speed sensor and transmitted to the control unit decreases. This antitone change can take place, according to need, in any manner, for example in stages with at least one stage, or continuously, in particular in proportion with, disproportionately lower or disproportionately higher than the relative speed.
According to a second aspect, the invention is directed to a motor vehicle comprising at least one of the exemplary devices according to the invention.
Each exemplary motor vehicle according to the invention preferably further comprises at least one speed sensor, which is connected to the control unit and detects or is able to detect the speed of the motor vehicle and transmits or is able to transmit it to the control unit.
Each exemplary motor vehicle according to the invention preferably further comprises                at least one distance sensor, which is connected to the control unit and detects or is able to detect the distance of the motor vehicle from an object located in front of the motor vehicle in the direction of travel and/or from a vehicle travelling in front, and transmits or is able to transmit it to the control unit;        
wherein                the control unit changes or is able to change the first and/or the second threshold value according to an isotone function of the distance.        
The distance sensor can, according to need, be formed in any way and can function, for example, with laser light and/or LIDAR and/or RADAR and/or ultrasonics.
Each exemplary motor vehicle according to the invention preferably further comprises                at least one relative speed sensor, which is connected to the control unit and detects or can detect the relative speed of the motor vehicle with respect to a vehicle travelling in front and transmits or can transmit it to the control unit;        
wherein                the control unit changes or is able to change the first and/or the second threshold value according to an antitone function of the relative speed.        
The relative speed sensor can, according to need, be formed in any way and can function, for example, with laser light and/or LIDAR and/or RADAR and/or ultrasonics.
Each exemplary device and each exemplary motor vehicle according to the invention preferably further comprises at least one moving image source for the moving images, which are connected to the screen, for example directly or indirectly, in particular via the control unit, and/or at least one slot for the connection of a moving image source, which is connected to the screen, for example directly or indirectly, preferably via the control unit.
The moving image source can, according to need, be formed in any manner, for example as an analogue and/or digital TV tuner, DVD player, Blu-ray player, external hard drive, flash memory card or USB stick.
In the exemplary devices and the exemplary motor vehicles according to the invention, provision can be made for                the second threshold value to be greater than the first threshold value;        the control unit to remain in the first mode if the first threshold value is reached or exceeded, and to switch from the first mode to the second mode if the second threshold value is reached or exceeded;        the control unit to remain in the second mode if the first threshold value is fallen below, and to switch from the second mode to the first mode if the first threshold value is fallen below.        
The threshold values can be selected in any way according to need. Thus, for example, the first threshold value can be 3 km/h and the second threshold value can be 5 km/h.
Since the control unit only switches to the second mode when the second threshold value has been reached or exceeded, and only switches to the first mode when the first threshold value is fallen below, it selects the modes according to the type of hysteresis.
In the exemplary devices and the exemplary motor vehicles according to the invention, provision can be made for the control unit to only function in the second mode if the time span, during which the speed is greater than or equal to the second threshold value, is greater than a predetermined minimum value.
Since the control unit only functions in the second mode or switches from the first mode to the second mode after the expiry of this time span, the second mode is activated with a delay that corresponds to the minimum value. This enables a smoother journey in traffic jams and slow-moving traffic.
The minimum value can, according to need, be selected in any way and is, for example, 10 s.
In the exemplary devices and the exemplary motor vehicles according to the invention, provision can be made, in the second mode, for the control unit to change or be able to change the refresh rate according to an antitone function of the speed and/or time.
Since the control unit changes or can change the refresh rate according to an antitone function of the speed and/or time, it reduces the respective threshold value or leaves it unchanged if the speed and/or time detected by the speed sensor and transmitted to the control unit increases, and it enlarges the refresh rate or leaves it unchanged if the speed detected by the speed sensor and transmitted to the control unit decreases. This antitone change can take place, according to need, in any manner, for example in stages with at least one stage, or continuously, in particular in proportion with, disproportionately lower or disproportionately higher than the speed and/or time.
According to a third aspect, the invention is directed to a method for displaying moving images in a motor vehicle, in particular in one of the proposed motor vehicles and/or with the aid of one of the proposed devices, wherein                the moving images are displayed in at least one first mode with normal playback parameters and one second mode;        the speed of the motor vehicle is detected;        the first mode is selected if the speed is less than a first threshold value;        the second mode is selected if the speed is greater than or equal to a second threshold value that is greater than or equal to the first threshold value;        in the second mode, the refresh rate is lower than in the first mode.        
Exemplary embodiments of the method can involve                the second threshold value to be greater than the first threshold value;        the first mode to remain selected if the first threshold value is reached or exceeded, and to be switched from the first mode to the second mode if the second threshold value is reached or exceeded;        the second mode remains selected if the first threshold value is fallen below, and is switched from the second mode to the first mode if the first threshold value is fallen below.        
According to exemplary embodiments the moving images are only displayed in the second mode if the time span, during which the speed is greater than or equal to the second threshold value, is greater than a predetermined minimum value.
In the second mode, provision can be made for the refresh rate to be changed according to an antitone function of the speed and/or time.
According to exemplary embodiments the method can involve                detecting the distance of the motor vehicle to an object located in front of the motor vehicle in the direction of travel and/or to a vehicle travelling in front;        changing the first and/or the second threshold value according to an isotone function of the distance.        
According to exemplary embodiments the method can involve                detecting the relative speed of the motor vehicle to a vehicle travelling in front;        changing the first and/or the second threshold value according to an antitone function of the relative speed.        
In the exemplary devices according to the invention, the motor vehicles and the methods, the refresh rate in the second mode is 0 Hz.
Then, for example, the frame of the moving images that is currently being displayed or was most recently displayed can be displayed as still or frozen image.
In the proposed devices, the proposed motor vehicles and the proposed methods, provision can be made for the image resolution and/or the color depth and/or the brightness to be smaller in the second mode than in the first mode.
The reduction in image resolution can, for example, be carried out by reducing the pixel density in the form of pixelization. The reduction in color depth can, for example, lead to a depiction of the moving images in greyscale or in black and white. The reduction in brightness can, for example, lead to a darker depiction of the moving images.
The embodiments of the inventive devices, in particular individual features of the proposed devices, apply accordingly and analogously for the inventive motor vehicles and the inventive methods. The embodiments of the inventive motor vehicles, in particular individual features of the inventive motor vehicles, apply accordingly and analogously for the inventive devices and the inventive methods. The embodiments of the inventive methods, in particular individual features of the inventive methods, apply accordingly and analogously for the inventive devices and the inventive motor vehicles.